This disclosure relates to wire rope cutters. More particularly, this disclosure relates to wire rope cutters with a compound mechanical advantage.
Existing cutting tools which may use a mechanical advantage are sometimes used in the arbor industry for cutting small diameter wire rope. Some existing cutters supposedly utilizing a compound mechanical advantage so that the cutting jaws are better enabled to open further. The opposite is actually the case. The handles must be opened further than with a single stage cutter in order to open an equivalent amount to a single stage cutter.
An example of an existing cutter is shown in U.S. Pat. No. 92,202. However, the cutter mechanism in U.S. Pat. No. 92,202 is used in the arbor industry and does not save space or overall length.
Existing cutting tools utilize a fulcrum method to generate additional force for the purpose of cutting through wire rope. (See FIG. 1). This results in a mechanical advantage which is typically defined as the ratio of the output force created by a mechanism divided by the applied input force. However, due to the length of a handle from a pivot compared to the length of the cutting jaw, a single mechanical advantage is developed. The mechanical advantage (MA) is defined as the pivot handle length divided by the pivot jaw length or:MA=Pivot Handle Length/Pivot Jaw Length
Another compound wire rope cutter is shown in Published Application No. US 2013/0247385 which is incorporated by reference herein. Referring to FIG. 9, a problem with this cutter 11 is the original cutter blades B, 15 had insufficient bearing area 17, thus allowing the cutter blades to twist and the main pivot screw to elongate under the heavy loading of cutting large diameter cables. This deformation creates a gap between the blades during actual cutting of cables and the strands of the cable get caught in the gap. Consequently, the cut is incomplete and the cutter is jammed. An example of this would be trying to cut a thick, tough piece of material with an ordinary hand scissor. The material would get stuck between the blades. Thus, there exists a need for a wire rope cutter which is much more rigid with increased bearing area and has two screws holding the cutter halves together.
Thus, there exists a need for a wire rope cutter which has a compound mechanical advantage. There also exists a need for a compound cutter which is nested and has a reduced overall length.
There also exists a need for an increase in bearing area for cutter blades for increasing the rigidity and stiffness of the cutter blades.
Other benefits and aspects of the disclosure will become apparent upon a reading and understanding of the following detailed description.